Oxidized all-weather cutback asphalts

ABSTRACT

Fully oxidized cutback asphalts suitable for application in roofing, waterproofing, and sealing applications in all weather conditions, including as mastics and other sealants. Compositions according to the invention comprise unprecedented proportions of solids and asphalts yet remain workable to temperatures as low as 20° F. or below. In addition to fully-oxidized roofing-grade asphalts, preferred compositions according to the invention also comprise hydrophobic agents selected from the group comprising fatty acids and amine compounds and may be applied in rain or other wet conditions, and include polybutene or fatty acid peptizers to control the glass transition temperature of the completed mastic and thereby permit application of the composition at extremely low temperatures. Preferred embodiments optionally also comprise fillers such as cellulose fibers, diatomaceous earth, limestone, and asbestos for various advantageous purposes.

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/122,190, now U.S. Pat. No. 6,087,419, entitled OxidizedAll-Weather Cutback Asphalts and filed Jul. 23, 1998.

TECHNICAL FIELD

The invention relates to asphalt based waterproofing, roofing, andsealing compounds; more particularly, it relates to fully oxidizedcutback asphalt mastics, coatings, and sealants suitable for applicationin all weather conditions.

BACKGROUND OF THE INVENTION

For centuries asphalt and other bituminous products have been used toprovide waterproofing and protective coverings and coatings for roofs,foundations, and the like; resilient, weather resistant pavings; andsealants useful in a wide variety of applications. And for as long asasphalts have been used for such purposes it has been found necessaryfrom time to time to repair the installations of which they form part. Aparticularly vexing annoyance has been that those times at which theneed for repair is made most apparent, and at which the need for repairsis most sorely immediate, are those very times when it is both mostdifficult and least convenient to make them: for example, when it israining and/or temperatures are below freezing. Both moisture and cooltemperatures make it very difficult to apply or install asphaltcompounds, including mastics and other asphalts used in the repair ofexisting roofs, because asphalts typically do not adhere to damp or wetsurfaces and water and because they become highly viscous and even solidat reduced temperatures.

In addition, it has long been recognized that oxidizing the asphaltsused in each of the above mentioned applications produces results farsuperior to those achieved by using unoxidized, straight-run or “flux”asphalts. Among other effects, the oxidization of asphalt raises itssoftening point—which in most roofing, sealing, and waterproofingapplications is desirable. For example, it is desirable to use anasphalt having a softening point in excess of 100° F. on roofs exposedto warm summer sun, which can cause temperatures in the asphalt toexceed the typical 70° softening point of unoxidized asphalts by aconsiderable margin. Yet the oxidation of asphalt and the consequentialelevation of its softening point aggravates the difficulty of applyingthe asphalt—with a higher softening point, the asphalt is even stifferthen before at any given temperature. In the past, the solution to theproblem of repairing leaks in asphalt roofing installations in inclementweather, using mastics and the like, has been addressed, as best may be,through the mixing of straight-run (unoxidized) asphalts, with theirinferior weather-resistant qualities and low softening points, withmineral spirits to form cutback asphalts. The mixing of asphalt withmineral spirit solvents to form cutback asphalts has the effect oflowering the softening point of the asphalt, so that it can be appliedat relatively low temperatures without heating. Once the cutback hasbeen installed, the mineral spirit cutback agent evaporates, leavingbehind only the asphalt base, together with any other added non-volatilesubstances such as bulk and insulation fillers. Yet even the use ofmineral spirit solvents as cutback agents can lower the softening point,or the viscosity, of an asphalt so far—at least, that is, whenacceptable amounts of the solvent are used. In order to make mostasphalt soft enough to be applied in cold temperatures, in excess of 60%mineral spirits (by weight) must typically be used, leaving a solids(asphalt) content of 40% or less. This reduces the solid (asphalt)content of the cutback to unacceptably low levels and reduces theviscosity, durability, and weather resistance of the residual asphaltcoating. Indeed, mineral spirit cutback asphalts used today generallyfail to meet accepted quality standards published by the AmericanSociety of Testing Materials (ASTM). The use of oxidized asphalts, withtheir elevated softening points and increased viscosity, has onlyaggravated the problem. Even more mineral spirits are used, leavingbehind even less solids content having even worse residual properties.And neither cutback nor straight paving grade asphalts have greateraffinity for water than any other asphalts, so that the use of suchasphalts in wet conditions to repair, for example, leaky roofs has beenunsatisfactory. Thus attempts to utilize the superior weather-resistantqualities available through the use of fully oxidized asphalts(sometimes called “air blown” asphalts in the industry) as bases for thecutback asphalts have consistently resulted in mixtures having eithermelting or softening points well above the point at which such asphaltscan be effectively applied in cold temperatures or far too high asolvent content, or both.

Other attempts have been made. For example, U.S. Pat. No. 5,362,316 toParadise discloses a composition comprising asphalt, coal tar,elastomers, and a terpene solvent; while U.S. Pat. No. 5,618,340 and5,622,554 to Krogh et al. disclose a roof-coating compositionscomprising alkylated fatty amines and alkoxylated ether aminesurfactants. None of these attempts, however, teaches a means forproducing mastics, coatings, or sealants which enjoy the benefits ofusing oxidized asphalts.

Thus there exists a need for an asphalt roofing, waterproofing, andsealing compound enjoying the benefits of a fully oxidized asphalt baseand suitable for use in cold weather and in damp or wet conditions,having acceptable viscosity over a broad range of temperatures and anacceptable solids content, and which meets accepted quality standardssuch as those published by the ASTM.

DISCLOSURE OF THE INVENTION

Accordingly, it is an object of the invention to provide an asphaltroofing, waterproofing, and sealing compound enjoying the benefits of afully oxidized asphalt base and suitable for use in cold weather and indamp or wet conditions, having acceptable viscosity over a broad rangeof temperatures and an acceptable solids content, and which meetsaccepted quality standards such as those published by the ASTM. It is afurther object of the invention to provide such an asphalt in the formof a mineral-spirit cutback. It is yet another object of the inventionto provide such an asphalt in a form which is capable of realizing thefurther benefits of modification by the addition of rubber or otherpolymers, and by the addition of various fillers to improve sag, creepcontrol, thermal insulation, and other properties in the finishedcutback asphalt installation.

These and such other objects of the invention as will become evidentfrom the disclosure below are met by the invention disclosed herein. Theinvention provides means and compositions for fully oxidized cutbackasphalts, including mastics and other sealants, suitable for applicationin roofing, waterproofing, and sealing applications under all weatherconditions. Compositions according to the invention compriseunprecedentedly high proportions of solids and asphalts content, yetremain workable to temperatures as low as 20° F. or below, and meet allapplicable ASTM standards. In addition, asphalt compounds according tothe invention are suitable for use with rubber- or otherpolymer-modified asphalt bases and benefit from the advantages orpolymer modification.

In one aspect the invention provides a fully oxidized all-weatherhydrophobic cutback asphalt capable of being applied to a substrate atan ambient temperature as low as approximately 20° F. without beingheated. The cutback asphalt exhibits improved adherence to wetsubstrates, and comprises between about 60% and about 80% by weightfully oxidized asphalt having a softening point between about 110° F.and 140 ° F., between about 20% and about 40% by weight mineral spirits,at least ½% and preferably between about 1% and about 6% by weightpolybutene, and optionally at least about ⅙% by weight of a hydrophobicagent selected from the group comprising fatty acids and amine compound.Alternatively, enough polybutene or other peptizer is used to permit thecutback asphalt to be spread upon a substrate at an ambient temperatureas low as approximately 20° F. without being heated, and to form asmooth surface on the substrate, so that an effective waterproof ormoisture-resistant barrier may be created. It has been found that aslittle as {fraction (1/10)}% by weight of peptizers of the typedescribed herein will serve; preferably between about 1% and about 10%,and most preferably about 5%, by weight peptizer is used. Preferredpeptizers for use with this aspect of the invention include polybutene,esters of fatty acids, and in particular glycerides of fatty acids.Preferred esters and glycerides include esters and glycerides oflinolenic, oleic, linoleic, and ricinoleic acids. For example, it hasbeen observed that in addition to polybutene, linseed oil and castoroil, which comprise significant amounts of glycerides of linolenic,oleic, linoleic, and ricinoleic acids serve very satisfactorily aspeptizers in practicing this aspect of the invention.

The asphalt comprised by the composition serves as a major component inbuilding the waterproofing, sealing, and protective coating of theinvention. Any asphalt capable of being oxidized to a softening point inthe specified range and consistent with the purposes stated herein willserve. For most applications, oxidized asphalts having a softening pointof about 100° F. or more are adequate, but best results have beenachieved by oxidizing the asphalt to a softening point of approximately120° F., and these asphalts are preferred for use with the invention.The mineral spirits act as the primary cutback agent, keeping theasphalt from solidifying at typical ambient temperatures. Prior artcutback asphalts remain workable to temperatures as low as 50° F. or so,due primarily to the presence of the mineral spirits. In an attempt tomake such cutbacks workable at temperatures much below 50° F., however,mineral spirit contents of 70% to 75% by weight, or even more, haveproved necessary, and these contain an unacceptably low solid contentsfor general roofing, waterproofing, and sealing use. And none of theprior art compositions employ 100% oxidized asphalt bases, with itssuperior weather resistant possibilities. An asphalt content of about60% to 80% and a cutback content of about 20% to about 40% by weight ispreferred because the viscosities of cutbacks in this composition rangeexhibit viscosities which facilitate the making of superior asphaltcoating layers. When too little cutback agent is present the asphalt isunworkably stiff at most desired temperature ranges, and when too muchcutback agent is present the asphalt has too low a viscosity whenapplied to permit formation of an adequate coating.

It is only by means of the improvements stated herein that cutbacksuseable at 20° F. and below are possible; and this is especially so inthe case of cutbacks having fully oxidized asphalt bases. Theimprovement is chiefly accomplished by the addition to cutback asphaltsof significant amounts of polybutene, which may be probably best bedescribed as a peptizer, but which may also be thought of as aplasticizer. It has been found that the addition to cutback asphalts ofsmall amounts of polybutene affects the glass transition characteristicsof the asphalt, lowering the viscosity of the cutback at lowtemperatures and raising the viscosity at high temperatures, both ofwhich are extremely beneficial in cutback asphalts, as they are easierto apply and more durable and less prone to sagging or creeping andother environmentally-induced effects once installed. It has been foundthat the benefits derived from the addition of polybutene are optimizedby adding between about 1% and about 6% polybutene having an averagemolecular weight (MN) of between about 900 and about 2500, a viscosityat 100° F. of between about 8,000 and about 150,000 cSt, and a densityof between about 7.4 and about 7.6 pounds per gallon (US); and mostpreferably about 2% to about 3% polybutene having an average molecularweight of about 1,300, a viscosity at 100° F. of about 27,230 cSt, and adensity of about 7.47 pounds per gallon (US). Adding too littlepolybutene has been found to have an inadequate effect on the glasstransition characteristics of the cutback asphalt to achieve thebeneficial results described, and in particular too small an effect onreducing the viscosity of the asphalt at low temperatures. Adding toomuch has been found to lead to phase change and a breakdown in theprocess whereby the polybutene is absorbed in the cutback composition,having no additional useful effect on the glass transitioncharacteristics beyond those provided by the mentioned preferred levels,and introducing sometimes unwanted excess compounds to the composition.

The optional addition to the cutback asphalt of a hydrophobic agent hasthe generally desirable effect of giving the cutback asphalt thecharacteristic of driving moisture away from itself without degradingthe quality of the asphalt itself or of the resultant coating, whichpermits the cutback asphalt to be applied confidently in wet or rainyconditions. Many hydrophobic agents are known and used with asphalts,particularly with those intended for application at ambient temperature,without added heat, as such asphalts must frequently be applied in wetweather and in other moist conditions. In addition to these knownhydrophobic agents, preferred hydrophobic agents for use with theinvention described herein include fatty acids and amine compounds,which are believed to have the additional beneficial effect of aidingthe introduction and incorporation of the polybutene or other peptizer.Fatty acids preferred in making those compounds according to theinvention which comprise rubber or polymer-modified asphalt bases, as ithas found that the use of amine compounds tends to react with thepolymer modifier, causing a phase separation after the finished producthas been allowed to set for a time. Fatty acids have not been found tocause or encourage this phase separation. It has been found that theaddition of about ⅙% to about ¾% by weight hydrophobic agent optimizesthe hydrophobic benefits of the agent. In the case of amine compounds,the addition of too much hydrophobic agent has been observed in someconditions to actually increase the attraction of moisture to theasphaltic compound—that is, to impart to the compound a hydrophilicrather than a hydrophobic or water-repellent tendency. It is alsoobserved that the addition of too much amine compound reduces theadhesiveness of the asphaltic compound, making it more difficult toinstall and reducing its effectiveness and its useful life.

As indicated, an especially advantageous aspect of the invention is thatit permits the use of fully oxidized asphalt bases, in particularasphalts modified by the addition of rubber and other polymers, as forexample styrene-ethylene-butylene-styrene (SEBS) block copolymer,styrene-butadiene-styrene (SBS) block copolymer, and atacticpolypropylene (APP). As more fully explained in my patent applicationsSer. No. 08/978,243, filed Nov. 25, 1997, and entitled “Styrene EthyleneButylene Styrene (SEBS) Copolymer Rubber Modified Asphalt Mixture” (nowU.S. Pat. No. 5,973,037); and U.S. Pat. No. 08/978,244, filed Nov. 25,1997, and entitled “Plasticized Styrene Ethylene Butylene Styrene (SEBS)Copolymer Rubber Modified Asphalt Mixture” (now U.S. Pat. 5,929,144).modified asphalts enjoy all of the advantages offered by unmodifiedasphalts, and many more, including increased resistance to thermalstresses, ozone, and ultraviolet radiation. Moreover, cutback asphaltsaccording to the invention described herein may be produced by themethods and apparatus described herein in the same manner thosecontaining nom-modified asphalts, without need for modifying the processor apparatus. The specifications for my SEBS modified asphalts arehereby incorporated in this specification, as if set out fully herein,to supplement the processes and explanations provided herein, and tosupport my teaching of the art of making polyester sheets coated withspecially modified asphalts. It is preferred to use modified asphaltscomprising from 1% to about 25% by weight styrene ethylene butylenestyrene (SEBS) copolymer, and in particular between about 3% to about 5%SEBS, before addition of solvents and other additives. SEBS is usedsatisfactorily in cutback asphalts according to the invention preparedwith either polybutene or other peptizers, as herein described.

It is also advantageous in many conditions to add various fillers to thecutback asphalts of the invention. Such fillers may include thoseselected from the group comprising cellulose fibers, diatomaceous earth,limestone, and asbestos. In addition to other properties contributed byspecific fillers, fillers in general can, as will be understood by thosehaving an ordinary familiarity with the art, be used to control oraffect the viscosity, bulk, and solids content of the finished cutbackproduct, as well as fire ratings, thermal insulation characteristics,creep (or sag), and weather resistance. Cellulose, limestone, anddiatomaceous earth are also especially useful for absorbing excess oilspresent in the asphalt. Many of these fillers, and especially limestone,are cost effective fillers, in that they are relatively inexpensive.

In adding cellulose fibers to the cutback asphalts of the invention, ithas been found to be advantageous to prepare the cutback for addition ofthe cellulose by adding a quantity of a colloidal attapulgite claygelling compound to aid suspension of the cellulose fibers in thecutback. In turn, dispersion of the colloidal attapulgite clay in saidcutback asphalt is improved by the addition of an active cationic saltsurfactant. Thus preferred embodiments of the invention comprisecolloidal attapulgite clays and cationic salt surfactants.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an apparatus for carrying out a preferredprocess for making fully-oxidized cutback asphalts according to theinvention.

FIG. 2 is a schematic plot of illustrative viscosities of cutbackasphalts according to the invention, compared to comparable prior artcompositions, as a function of temperature.

BEST MODE OF CARRYING OUT THE INVENTION

Asphalt, for the purposes of this disclosure, means any bituminousmaterial or hydrocarbon, with or without additives, fillers, oraggregates, having sufficient insolubility in water and viscosity to beused advantageously in roofing, sealing, paving, or waterproofing,whether naturally occurring or distilled from petroleum or likeproducts. In particular, asphalt includes, without limitation,straight-run asphalts or asphalts modified by the addition of rubbers orother polymers, coal, tar, and pitch, as well as all bitumens andmodified bituminous materials, whether oxidized or unoxidized. Bitumenssuch as asphalt having a softening point of between about 10° C. andabout 107° C. (50° F. and about 225° F.) with penetration at 77 degreesF. of about 12 to about 100{fraction (1/10)} millimeters maybe used asis or may be modified by the addition of rubber or other polymers, asfor example styrene-ethylene-butylene-styrene (SEBS) block copolymer,styrene-butadiene-styrene (SBS) block copolymer, and atacticpolypropylene (APP). An example of a flux asphalt which may be used togreat advantage in making either unmodified or rubber- or otherpolymer-modified asphalts for use with the invention is that sold underthe trade designation TOSCO by the U.S. Oil and Refining Company ofTacoma, Wash. One formulation of an SEBS copolymer used with greatadvantage in this invention is that provided in plasticized form byImperbel America Corporation of 717 South 38th, P.O. Box 6761, KansasCity, Kans, 66106, under a product designation of I 175.

Preferred cutback agents for use in making compositions according to theinvention comprise mineral spirits, including any of the commonindustrial grade mineral spirits, in particular those havingkauri-butanol (k.b.) values of 30 or greater, and flashpoints of 100° F.or greater. In particular, the mineral spirits available commerciallyfrom the Exxon Corporation under the trade name Varsol 3139 have beenfound to work satisfactorily with the cutback asphalts of the invention.

Polybutene means any polymer of isobutene ((CH₃)₂CCH₂). Whilepolybutenes having average molecular weights of between about 900 andabout 2500, viscosities at 100° F. of between about 8,000 and about150,000 cSt, and densities of between about 7.4 and about 7.6 pounds pergallon (US) are preferred, any polybutene which will accomplish thepurposes disclosed herein will serve. An example of a preferredpolybutene for use in making the compositions described herein isavailable under the trade designation PARAMINS PARAPOL 1300 from theExxon Chemical Company. This polybutene has an average molecular weightof about 1,300, a viscosity at 100° F. of about 27,230 cSt, and adensity of about 7.47 pounds per gallon (US). An alternative acceptablepolybutene is available under the trade designation INDOPOL H300.

A peptizer is any substance which aids in peptization of the cutbackasphalt compositions described herein. Peptization is any aggregation inwhich a colloidal mixture is stabilized by the addition of agents whichare adsorbed on particle surfaces, or any liquefaction of a substance byrelatively small amounts of another substance. Suitable peptizers foruse with this aspect of the invention include poylbutene, castor oil andlinseed oil, and esters and glycerides of fatty acids, including inparticular esters and glycerides oflinolenic, oleic, linoleic, andricinoleic acids.

An amine is a derivative of ammonia in which one or more of thehydrogens of ammonia (NH₃) is replaced by an alkyl group, e.g,, methyl(—CH₃), ethyl (—C₂H₅), or an aryl group, e.g., phenyl (—C₆H₅) ornaphthyl (—C₁₀H₇). An example of a preferred amine for use in making thecompositions described herein is dehydroabietyl amine, which isavailable under the trade designation HERCULES Amine D from HerculesIncorporated of Wilmington, Del.

A fatty acid is a monobasic organic acid derived from, for example, thesaturated series of aliphatic hydrocarbons or from natural fats andoils, and having the general formula C_(n)H_(2n+1)COOH. An example of acompound comprising such acids and suitable for use in making thecompositions herein is available under the trade designation MORLIFE,and in particular MORLIFE 3300, from Morton Performance Chemicals ofDanvers, Mass.

An example of a colloidal attapulgite clay compound suitable for theuses disclosed herein is that available under the trade designationMIN-U-GEL G35 from ITC Industrials of Quincy, Fla. An active cationicsalt suitable for the uses disclosed herein is available under the tradedesignation PA-14 Acetate from Tomah Products, Inc., of Milton, Wis.,and comprises isodecyloxypropyl amine acetate.

An example of diatomaceous earth (also sometimes known as silica,kieselguhr, siliceous earth, ceyssatite, tripolite, and infusorialearth) suitable for use for the purposes disclosed herein is availableunder the trade designation CELITE, and especially CELITE 522, from theCelite Corporation of Lompoc Calif.

An example of a cellulose filler suitable for use in accomplishing thepurposes disclosed herein is that cellulose available under the tradedesignations GEL-CEL, INTERFIBE 230, and INTERFIBE 250 from Interfibe ofPortage, Mich. Such fibers are available in various average lengths. Itis found that the use of a mix of relatively short and relatively longfibers is desireable in tailoring characteristics in the finishedcutbacks. The possibilities and appropriate lengths or mixes of lengthsfor achieving desired characteristics will not trouble one of ordinaryskill in the art of making asphalt coatings. A particularly efficaciousmeans for adding cellulose fibers to the compound during mixing has beenfound to be to load the fibers into a common insulation blower, such asthose used in the residential and commercial insulation industries, andto blow it into the mixing tank. This has been found to aid uniformmixing of the fibers and making a more consistent product.

Turning now to the drawings, the invention will be described in apreferred embodiment by reference to the numerals of the drawing figurewherein like numbers indicate like parts.

FIG. 1 is a schematic view of an apparatus for carrying out a preferredprocess for making fully-oxidized cutback asphalts according to theinvention. Apparatus 100 comprises flux holding tank 101; air still 110,which comprises tank 102 and one or more blowers 111; cutback storagetank 103; and mixing tank 104. In a preferred process for making a fullyoxidized all-weather hydrophobic cutback asphalt according to theinvention a flux asphalt is introduced to air still 110 from storagetank 101. To aid both in handling and oxidation of the asphalt, and inorder to increase the rate at which the asphalt oxidizes, it isgenerally preferable to introduce the asphalt to the storage tank at asomewhat elevated temperature, preferably between about 375° F. andabout 425° F., and most preferably about 400° F. In doing so it isadvantageous to run the flux asphalt through optional heater or heatexchanger 105.

The flux asphalt is placed in tank 102 of air still 110. One or moreblowers 111 are used to blow atmospheric air through the flux asphalt,causing atmospheric oxygen to combine with the asphalt. As the oxidationof asphalt is an exothermic reaction, it is not typically necessary toheat tank 102 of the air still in order to sustain the reaction andcomplete oxidation of the asphalt. The temperature of the tankultimately stabilizes at about 500° F. An incidental benefit ofoxidizing the asphalt in this manner is that many of the lightercomponents of the asphalt (the “light ends”) are either burned off orotherwise separated from the asphalt due to the elevated temperatures;in many cases they maybe removed and used for other purposes or merelyburned off. Once the reaction has begun to sustain itself the softeningpoint of the asphalt within the still is tested by drawing some of theasphalt off and allowing it to cool; the temperature of the softeningpoint is easily noted. A preferred process for checking the softeningpoint is detailed in ASTM Standard D36, the contents of which are hereinincorporated by reference. As previously noted, oxidation of the asphaltto the point at which it softens at 100° F. or higher is adequate, butbest results are acheived by oxidizing the asphalt to a softening pointof approximately 120° F.

In the preferred process for preparing the oxidized cutback asphalt ofthe invention as depicted in FIG. 1, once the asphalt has reached adesired level of oxidization, i.e., a desired softening point, it istransferred, as by means of a pump, to cutback storage tank 103 viapipeline 120. In storage tank 103 the oxidized asphalt is allowed tocool, preferably to about 350° F. or 375° F., and mixed with a cutbackagent, preferably mineral spirits as previously discussed. Mineralspirits are introduced to tank 103 from source 107 and mixed at lowshear levels until thoroughly mixed by means of mixer 112. In preferredcutbacks according to the invention, a ratio of about 70% by weightasphalt to about 30% by weight mineral spirits is used.

It is often preferred to produced cutback asphalts according to theinvention which enjoy the superior qualities of rubber- or other polymermodified asphalt bases, including improved resistance to weather,ultraviolet radiation, ozone, and thermal shock. When producing suchmodified asphalts according to the process herein described, it is oftenconvenient to combine the modifying rubber or other polymer in cutbackstorage tank 103, prior to introduction of the cutback agent, at aslightly higher temperature, as for example about 400° F. in the case ofSEBS block copolymer as described in the incorporated patent disclosuresand as illustrated in Example 2 below. Following blending of the asphaltand the modifying polymer, the asphalt is allowed to cool to 350° F. or375° F. as discussed, and the process continues as otherwise described.

After the desired proportions of asphalt and cutback agent have beenuniformly blended by the low-shear mixer, the cutback mixture is testedto ensure proper solids content by drying or baking a sample of thecutback asphalt in an oven and weighing the residual solids after allthe volatile elements have been driven off. Viscosity is also preferablychecked, using a Brookfield Viscositer, for a viscosity of 100 to 300Centipoise at the preferred softening point of 120° F.

As previously mentioned, the cutback asphalt fonned at this stage of theprocess has been found to have higher viscosity at low temperatures, andlower viscosity at high temperatures, than is desirable. Moreover, it isless hydrophobic than is desirable. Therefore the cutback asphalt istransferred to mixing tank 104, where it is allowed to cool to atemperature of about 175° F. to about 225° F., preferably about 200° F.,low shear mixer 113 is started, and enough polybutene to make up betweenabout 1% and about 6% by weight of the finished cutback asphalt, orenough other peptizer to ensure that the asphalt can be appliedsatisfactorily at low temperatures, is added and mixed thoroughly. Ithas been found that as little as {fraction (1/10)}% by weight ofpeptizers of the type described herein will serve; preferably betweenabout 1% and about 10%, and most preferably about 5%, by weight peptizeris used. Again, preferred peptizers for use with this aspect of theinvention include polybutene, esters of fatty acids, and in particularglycerides of fatty acids. Preferred esters and glycerides includeesters and glycerides of linolenic, oleic, linoleic, and ricinoleicacids. Satisfactory and commercially easily available sources of suchpeptizers include linseed oil and castor oil. Enough hydrophobic agentto make up between about ⅙% to about ¾% by weight of the finishedcutback asphalt is added and thoroughly mixed. Finally fillers or otheradditives, such as cellulose fibers, diatomaceous earth, limestone, orasbestos are added, together with enough additional oxidized baseasphalt, mineral spirits, and cutback asphalt to achieve a desireableviscosity are added. Preferred compositions have viscosities, whenfinished, of approximately 40,000 to 90,000 centipoise at 120° F., andapproximately 300,000-500,000 at room temperature. When the resultantmix has been thoroughly blended it is removed from the mixing tank andplaced in containers for sale, for example in 1, 3, or 5 gallon cans, 11ounce tubes, and truckloads.

The particular specifications and capacities of the apparatus used inproducing cutback asphalts according to the invention will vary,depending upon the amount of cutback to be produced, the manner in whichit is to be sold, and desired additives. But the sizing and selectionofstorage and mixing tanks, mixers, blowers, pumps, valves, etc., willbe a matter well within the ability of those having ordinary familiaritywith the design, construction, and operation of asphalt plants andrequirements. In making quantities of cutback asphalts of the typedescribed suitable for commercial sale, one particularly satisfactorycombination has been found to comprise a 25,000 gallon storage tank 101;a 100-ton capacity air still 110 comprising a 25,000 gallon tank 102 andtwin WHISPAIR Rotary Lobe Blowers 111, Model No. 852-495-20 from theRoots Company of Connersville, Id., each having a normal rated capacityof 2,800 cubic feet per minute at the required operating pressure; a20,000 to 30,000 gallon cutback storage tank 103, with a Model 10-SV2S-410 h.p. Side Entry Mixer/Agitator 112 manufactured by the Burhans-SharpeCompany of Seattle, Wash., and having a rated speed of 100-300 RPM,installed and operating at about 200 RPM; and a total of 4 1,000 gallonvertical mixing tanks 104, each having a Baldor Super E 15 HP motor 113,model number CEM2333T, rated at 1,750 RPM geared down through aSEW-Eurodrive type SF92LP254TC-KS gearbox to between 90 and about 150RPM, preferably about 120 RPM. This combination permits the productionof 4,000 gallon lots, with 4 1,000 batches of fully oxidized hydrophobiccutback asphalt, each optionally containing unique combinations offillers and other additives.

FIG. 2 is a schematic plot of representative illustrative viscosities ofcutback asphalts according to the invention, compared to comparableprior art compositions, as a function of temperature. Broken line Arepresents illustrative data for a mineral spirit cutback asphaltcomprising 70% by weight fully oxidized asphalt and 30% by weightmineral spirits, with cellulose, diatomaceous earth, and limestoneadditives according to Example 1 below, but without polybutene or anyother peptizer, or any hydrophobic agent as contemplated in theinvention. Unbroken line B represents an identical asphalt according toExample 1 but containing 2% by weight polybutene and significant amountsof an amine compound. It is apparent from a comparison of the two curvesthat the addition of polybutene and a hydrophilic agent according to theinvention has substantial results on the viscosity of the cutbackasphalt, both at high and low temperatures: at low temperatures theviscosity is substantially reduced, while at high temperatures viscosityis increased. In both cases the change is beneficial: at lowtemperatures the cutback asphalt is more readily workable, while at hightemperatures the asphalt exhibits much greater resistance to sag andcreep than the composition not containing polybutene. It is believedthat the greatest contribution to changing the viscosity characteristicsof the asphalt, that is, to the effect in the glass transitiontemperature of the asphalt, is due to the addition of polybutene orother peptizers as discussed.

EXAMPLE 1

A fully-oxidized all-weather hydrophobic cutback mastic is producedusing the apparatus described above. Approximately 25,000 gallons ofTOSCO brand flux asphalt is oxidized to a softening point of 120° F. byplacing it in a 30,000 gallon capacity air still and blowing air throughthe asphalt at a rate of 5,500 cubic feet per minute for three hours.When it has been established through testing according to the standardsof ASTM D36 that a 120° F. softening point has been attained, 140,000pounds of the asphalt are pumped to a 30,000 gallon capacity verticalmixing tank and allowed to cool to between 350° F. and 375° F. 60,000pounds of VARSOL brand mineral spirits are added to the tank and blendedwith the asphalt at 200 RPM using a Burhans-Sharpe Model 10-SV2S-4 10h.p. Side Entry Mixer/Agitator for two hours to make approximately25,000 gallons of thoroughly mixed, fully oxidized mineral spiritcutback asphalt comprising 30% mineral spirits and 70% asphalt byweight. The solids content is checked and viscosity is checked foravalue of 200 centipoise at 120° F. The cutback asphalt is allowed tocool to under 200° F., and 400 gallons of the asphalt is transferred toa 1,000 gallon capacity vertical mixing tank. The asphalt is agitated atlow speed, approximately 50 RPM, and 10 gallons of PA-14 Acetate activecationic salt is added and allowed to disperse within the asphaltmixture for five minutes, at which point 550 pounds of MEN-U-GEL G35colloidal attapulgite clay compound is added. This mixture is allowed toblend for 15 minutes. During this period the viscosity increasesnoticeably, primarily due to the presence of the clay. Twenty gallons ofParapol 1300 polybutene is then added and allowed to dispersethoroughly. An additional 100 gallons of cutback asphalt is added fromthe cutback storage tank to thin the mixture slightly, and allowed toblend until a uniform consistency is acquired. Two hundred pounds ofInterfibe 230 cellulose filler are added by means of an insulationblower as described above, and mixed until a uniform consistencyresults. Another 100 gallons of cutback is added, to thin the mix, andmixed until uniform. Three gallons of HERCULES Amine D is added as ahydrophobic agent and mixed thoroughly, and 250 pounds of Interfibe JMMcellulose fibers are added. When the mix is again uniform 400 pounds ofCelite 522 diatomaceous earth and 100 pounds of limestone are added,followed by another 200 gallons of cutback. The resultant compound ismixed for 30 minutes to insure a uniform blend. To ensure uniformity themixer is set up to create a top-to-bottom circulation within the tank.Samples are taken to ensure a viscosity of 40,000 to 60,000 centipoiseat 120° F. and of 300,000 to 400,000 centipoise at room temperature.

Approximately 900 gallons of fully oxidized all-weather hydrophobiccutback asphalt capable of being applied to a substrate at an ambienttemperature as low as approximately 20° F. without being heated, andexhibiting improved adherence to a wet substrate results. The compoundis packed in 1 gallon, 3 gallon and 5 gallon cans, 11 ounce tubes, andtruck tanks for use. It may be used for general membrane patching,sealing, roofing, and waterproofing.

EXAMPLE 2

A fully-oxidized SEBS-modified all-weather hydrophobic cutback mastic isproduced using the apparatus described above. Approximately 25,000gallons of TOSCO brand flux asphalt is oxidized to a softening point of120° F. by placing it in a 30,000 gallon capacity air still and blowingair through the asphalt at a rate of 5,500 cubic feet per minute forthree hours. When it has been established through testing according tothe standards of ASTM D36 that a 120° F. softening point has beenattained, the asphalt is allowed to cool to approximately 400° F. Fivethousand six hundred (5600) pounds of Imperbel I 175 gelled bricks ofplasticized SEBS compound are placed in a 30,000 gallon capacityvertical mixing tank, and 134,400 of the 400° F. oxidized asphalt areadded; these are mixed for approximately 30 minutes until a uniformpolymer modified asphalt results. The polymer modified asphalt isallowed to cool to between 350° F. and 375° F., and 60,000 pounds ofVARSOL brand mineral spirits are added to the tank and blended with themodified asphalt at 200 RPM using a Burhans-Sharpe Model 10-SV2S-4 10h.p. Side Entry Mixer/Agitator as described above for two hours to makeapproximately 25,000 gallons of thoroughly mixed, fully oxidized mineralspirit cutback asphalt comprising 30% mineral spirits and 70%polymer-modified asphalt by weight. The solids content is checked andviscosity is checked for a value of 100 to 300 centipoise at 120° F. Themodified cutback asphalt is allowed to cool to under 200° F., and 400gallons of the asphalt is transferred to a 1,000 gallon capacityvertical mixing tank. The asphalt is agitated at low speed,approximately 50 RPM, and 10 gallons of PA-14 Acetate active cationicsalt is added and allowed to disperse within the asphalt mixture forfive minutes, at which point 600 pounds of MIN-U-GEL G35 colloidalattapulgite clay compound is added. This mixture is allowed to blend for15 minutes. During this period the viscosity increases noticeably,primarily due to the presence of the clay. Twenty gallons of Parapol1300 polybutene is then added and allowed to disperse thoroughly. Anadditional 100 gallons of cutback asphalt is added from the cutbackstorage tank to thin the mixture slightly, and allowed to blend until auniform consistency is acquired. Two hundred pounds of Interfibe 230cellulose filler are added by means of an insulation blower as describedabove, and mixed until a uniform consistency results. Another 100gallons of cutback is added, to thin the mix, and mixed until uniform.Five gallons of Morton MORLIFE 3300 are added as a hydrophobic agent andmixed thoroughly, and 250 pounds of Interfibe JMM cellulose fibers areadded. When the mix is again uniform 400 pounds of Celite 522diatomaceous earth, followed by another 200 gallons of cutback. Theresultant compound is mixed for 30 minutes to insure a uniform blend. Toensure uniformity the mixer is set up to create a top-to-bottomcirculation within the tank. Samples are taken to ensure a viscosity of40,000 to 60,000 centipoise at 120° F. and of 300,000 to 400,000centipoise at room temperature.

Approximately 900 gallons of fully oxidized polymer-modified all-weatherhydrophobic cutback asphalt capable of being applied to a substrate atan ambient temperature as low as approximately 20° F. without beingheated, and exhibiting improved adherence to a wet substrate andsuperior resistance to weathering and exposure to ultraviolet rays andozone results. The compound is packed in 1 gallon, 3 gallon and 5 galloncans, 11 ounce tubes, and truck tanks for use. It may be used forgeneral membrane patching, sealing, roofing, and waterproofing.

EXAMPLE 3

A fully-oxidized all-weather hydrophobic cutback mastic is producedusing the apparatus described above. Approximately 25,000 gallons ofTOSCO brand flux asphalt is oxidized to a softening point of 120° F. byplacing it in a 30,000 gallon capacity air still and blowing air throughthe asphalt at a rate of 5,500 cubic feet per minute for three hours.When it has been established through testing according to the standardsof ASTM D36 that a 120° F. softening point has been attained, 140,000pounds of the asphalt are pumped to a 30,000 gallon capacity verticalmixing tank and allowed to cool to between 350° F. and 375° F. 60,000pounds of VARSOL brand mineral spirits are added to the tank and blendedwith the asphalt at 200 RPM using a Burhans-Sharpe Model 10-SV2S-4 10h.p. Side Entry Mixer/Agitator for two hours to make approximately25,000 gallons of thoroughly mixed, fully oxidized mineral spiritcutback asphalt comprising 30% mineral spirits and 70% asphalt byweight. The solids content is checked and viscosity is checked for avalue of 200 centipoise at 120° F. The cutback asphalt is allowed tocool to under 200° F., and 500 gallons of the asphalt is transferred toa 1,000 gallon capacity vertical mixing tank. Six hundred pounds ofasbestos fiber and 800 pounds of limestone are added, in alternatingportions of approximately 100 pounds, and observing accepted standardsfor safety and minimizing exposure to the asbestos, with 5 gallons ofMorton MORLIFE 3300, 30 gallons of Parapol 1300 polybutene, and 300pounds of Celite 522 diatomaceous earth. Once all the components havebeen added the mixture is blended for 10 minutes, until a uniformdistribution has been accomplished, and 60 gallons of VARSOL mineralspirits are added. This mixture is blended another five minutes, and 300gallons of cutback asphalt are added. After a uniform distribution hasbeen ensured by 30 minutes of mixing, the compound is processed via aSiefer Trigonal model no. SM 290/HK colloidal mill (available fromSiefer Maschinenfabrik GmbH and Co. K.G. through Siefer America Inc.) toensure full breakdown and incorporation of the asbestos fibers. Samplesare taken to ensure a viscosity of 60,000 to 90,000 centipoise at 120°F. and of 400,000 to 600,000 centipoise at room temperature.

Approximately 900 gallons of fully oxidized all-weather hydrophobiccutback asphalt capable ofbeing applied to a substrate at an ambienttemperature as low as approximately 20° F. without being heated, andexhibiting improved adherence to wet substrates and enhanced thermalinsulation qualities results. The compound is packed in 1 gallon, 3gallon and 5 gallon cans, 11 ounce tubes, and truck tanks for use. Itmay be used for general membrane patching, sealing, roofing, andwaterproofing.

EXAMPLE 4

A fully-oxidized all-weather hydrophobic cutback mastic is producedusing the apparatus described above, as described in Example 1, exceptthat instead of polybutene about 5% by weight linseed oil or castor oilis added. This ensures that when the cutback mixture is applied at lowtemperature an effective waterproofing or moisture-resistant membranecan be formed. Hydrophobic agents, biocides, and fillers are then addedas described.

Relative proportions of the components of the compounds described inExamples 1-3, given as parts and percentages by weight, are shown inTable 1.

Example 1 Example 2 Example 3 Ingredient Parts % Parts % Parts % Cutbackasphalt 5840 76.9 5840^((a)) 77.2 5840 70.8 Active cationic salt 77.41.0 77.4 1.0 — — Colloidal attapulgite clay 550 7.9 600 7.9 — —Polybutene 150 2.0 150 2.0 225 2.7 Cellulose fiber filler 450 5.9 4506.0 — — Amine compound 25 0.3 — — — — Fatty acid compound — — 44 0.6 440.5 Diatomaceous earth filler 400 5.3 400 5.3 300 3.6 Limestone filler100 1.3 — — 800 9.7 Asbestos — — — — 600 7.3 Additional (pure) mineral —— — — 440 5.3 spirits Totals 7592 100^((b)) 7561 100^((b)) 8249100^((b)) ^((a))SEBS polymer-modified cutback asphalt. ^((b))Numbers maynot add to 100 due to rounding.

With regard to systems and components above referred to, but nototherwise specified or described in detail herein, the workings andspecifications of such systems and components and the manner in whichthey may be made or assembled or used, both cooperatively with eachother and with the other elements of the invention described herein toeffect the purposes herein disclosed, are all believed to be well withinthe knowledge of those skilled in the art. No concerted attempt torepeat here what is generally known to the artisan has therefore beenmade.

INDUSTRIAL APPLICABILITY

The invention has applicability in the roofing, waterproofing, andsealing industries. In particular, the invention represents an advancein the usefulness, effectiveness, ease of installation, durability,weather resistance, and resistance to ultraviolet rays and ozone ofmineral spirit cutback asphalt-based roofing, sealing, and waterproofingcompounds.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural features. It is to beunderstood, however, that the invention is not limited to the specificfeatures shown, since the means and construction shown comprisepreferred forms of putting the invention into effect. The invention is,therefore, claimed in any of its forms or modifications within thelegitimate and valid scope of the appended claims, appropriatelyinterpreted in accordance with the doctrine of equivalents.

I claim:
 1. A fully oxidized all-weather hydrophobic cutback asphaltcomprising: between about 60% and about 80% by weight fully oxidizedasphalt having a softening point between 110° F. and about 140° F.;between about 20% and about 40% by weight mineral spirits; and enoughpeptizer to permit the cutback asphalt to be spread upon a substrate atan ambient temperature as low as approximately 20° F., without beingheated.
 2. The cutback asphalt of claim 1, wherein the peptizer is anester of a fatty acid.
 3. The cutback asphalt of claim 1, wherein thepeptizer is a glyceride of a fatty acid.
 4. A fully oxidized all-weatherhydrophobic cutback asphalt comprising: between about 60% and about 80%by weight fully oxidized asphalt having a softening point between 110°F. and about 140° F.; between about 20% and about 40% by weight mineralspirits; and enough peptizer to permit the cutback asphalt to be spreadupon a substrate at an ambient temperature as low as approximately 20°F., without being heated, the peptizer comprising one or more glyceridesselected from the group consisting of linolenic, oleic, linoleic, andricinoleic acids.
 5. The cutback asphalt of claim 1, further comprisingat least about ⅙% by weight of a hydrophobic agent.
 6. The cutbackasphalt of claim 5, wherein the hydrophobic agent is selected from thegroup consisting of fatty acids and amine compounds.
 7. The cutbackasphalt of claim 1, further comprising at least approximately 1% byweight polymer modifier.
 8. The cutback asphalt of claim 1, furthercomprising fillers selected from the group consisting of cellulosefibers, diatomaceous earth, limestone, and asbestos.
 9. The cutbackasphalt of claim 7, further comprising fillers selected from the groupconsisting of cellulose fibers, diatomaceous earth, linestone, andasbestos.
 10. A fully oxidized all-weather hydrophobic cutback asphaltcomprising: between about 60% and about 80% by weight fully oxidizedasphalt having a softening point between 110° F. and about 140° F.;between about 20% and about 40% by weight mineral spirits; enoughpeptizer to permit the cutback asphalt to be spread upon a substrate atan ambient temperature as low as approximately 20° F., without beingheated; cellulose fibers as fillers; and a colloidal attapulgite claygelling compound, whereby suspension of the cellulose fibers in thecutback asphalt is improved.
 11. The cutback asphalt of claim 10,further comprising an active cationic salt surfactant, wherebydispersion of said colloidal attapulgite clay in said cutback asphalt isimproved.
 12. A fully oxidized all-weather hydrophobic cutback asphaltcomprising: between about 60% and about 80% by weight fully oxidizedasphalt having a softening point between 110° F. and about 140° F.;between about 20% and about 40% by weight mineral spirits; enoughpeptizer to permit the cutback asphalt to be spread upon a substrate atan ambient temperature as low as approximately 20° F., without beingheated at least approximately 1% by weight polymer modifer; cellulosefibers as fillers; and a colloidal attapulgite clay gelling compound,whereby suspension of the cellulose fibers in the cutback asphalt isimproved.
 13. The cutback asphalt of claim 12, further comprisisng anactive cationic salt surfactant, whereby dispersion of said colloidalattapulgite clay in said cutback asphalt is improved.